The present invention relates to surface movement guidance systems for traffic on airfield pathways adapted to convey to the vehicle operators information regarding the position of a vehicle, particularly when visibility is poor.
Ground safety remains a problem at busy airports across the United States. The movement of aircraft in and around busy airports along taxiways between terminal gates and runways presents numerous opportunities for runway incursions, particularly when visibility is poor. A runway incursion is the entry of an aircraft without clearance onto an active runway from an adjacent ramp or taxiway, for which there is a great deal of risk of collision with a landing or departing aircraft. Incursions are often the inadvertent result of pilot disorientation caused by poor visibility.
As recently as Dec. 3, 1990, in an accident attributed to fog-reduced visibility, a Northwest Airlines jet at Detroit Metropolitan Airport took two wrong turns and taxied in front of another Northwest Airlines jet that was taking off, resulting in a collision that killed eight people. A runway incursion by a fog-disoriented pilot who mistook an active runway for a taxiway resulted in the worst disaster in aviation history when the ground collision of two Boeing 747 jetliners at Tenerife Airport in the Canary Islands in March 1977 resulted in the deaths of 583 people.
In 1990 in the United States alone, over 250 runway incursion incidents were reported. This does not include incidents such as taxiway collisions or near-misses resulting from vehicle operators mistaking one taxiway for another. Runway incursions and other taxiway incidents can still represent inconvenience and expense even when a ground collision does not result. To return an aircraft to a path from which it has strayed requires a considerable expenditure of time and fuel, and a compromise to the safety of all involved.
Guidance systems are known that assist taxiing aircraft in finding the centerline of taxiways and runways during poor visibility conditions, such as disclosed by U.S. Pat. No. 3,662,977 to Shannon. Airport pathways such as runways and taxiways are routinely marked at either or both ends by signs adjacent to the pavement or pavement markings. However, these signs and pavement markings are not visible from most locations on the runway or taxiway during conditions of poor visibility.
Lighted runway guidance systems are also known that illuminate the paths to be followed by an aircraft on a taxiway or runway when taking off and landing at night and when visibility is poor. Airport Surface Detection Systems are currently under procurement for major U.S. airports that utilize advanced ground-mapping radar to control aircraft and ground vehicles during inclement weather. However, such systems will not be procured for every airport, and, regardless, there remains a need for a simple, easily-installed system that identifies the path and the location and identity of intersecting pathways for pilots, especially during periods of poor visibility.